This invention relates to assembling an epicyclic gear train employed to drive a turbo fan.
Gas turbine engines may employ an epicyclic gear train connected to a turbine section of the engine, which is used to drive the turbo fan. In a typical epicyclic gear train, a sun gear receives rotational input from a turbine shaft through a compressor shaft. A carrier supports intermediate gears that surround and mesh with the sun gear. A ring gear surrounds and meshes with the intermediate gears. In arrangements in which the carrier is fixed against rotation, the intermediate gears are referred to as “star” gears and the ring gear is coupled to an output shaft that supports the turbo fan. In arrangements in which the ring gear is fixed against rotation, the intermediate gears are referred to as “planetary” gears and the carrier is coupled to the output shaft that supports the turbo fan.
The housings are typically split along a central plane, and the gear train can be assembled, with the carrier housing halves then being brought together and secured. For improved strength and rigidity, as compared with a two-part housing, it is desirable for an epicyclic gear train to have a unitary carrier housing.